M306V5ME-XXXSP Datasheet, PDF (55/263 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER and ON-SCREEN DISPLAY CONTROLLER

MITSUBISHI MICROCOMPUTERS
M306V5ME-XXXSP
M306V5EESP
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER
and ON-SCREEN DISPLAY CONTROLLER
2.7.19 Precautions for Interrupts
(1) Reading address 0000016
• When maskable interrupt is occurred, CPU read the interrupt information (the interrupt number and
interrupt request level) in the interrupt sequence.
The interrupt request bit of the certain interrupt written in address 0000016 will then be set to “0”.
Reading address 0000016 by software sets enabled highest priority interrupt source request bit to “0”.
Though the interrupt is generated, the interrupt routine may not be executed.
Do not read address 0000016 by software.
(2) Setting the stack pointer
• The value of the stack pointer immediately after reset is initialized to 000016. Accepting an interrupt
before setting a value in the stack pointer may become a factor of runaway. Be sure to set a value in
the stack pointer before accepting an interrupt.
(3) External interrupt
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• Either an “L” level or an “H” level of at least 250 ns width is necessary for the signal input to pins INT0
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and INT1 regardless of the CPU operation clock.
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•When the polarity of the INT0 and INT1 pins is changed, the interrupt request bit is sometimes set to
“1”. After changing the polarity, set the interrupt request bit to “0”. Figure 2.7.14 shows the procedure
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for changing the INT interrupt generate factor.
Rev. 1.0
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